/*
 * Copyright (c) 1994, 2013, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 */

package java.lang;

import sun.misc.FloatingDecimal;
import sun.misc.FloatConsts;
import sun.misc.DoubleConsts;

/**
 * The {@code Float} class wraps a value of primitive type
 * {@code float} in an object. An object of type
 * {@code Float} contains a single field whose type is
 * {@code float}.
 *
 * <p>In addition, this class provides several methods for converting a
 * {@code float} to a {@code String} and a
 * {@code String} to a {@code float}, as well as other
 * constants and methods useful when dealing with a
 * {@code float}.
 *
 * @author Lee Boynton
 * @author Arthur van Hoff
 * @author Joseph D. Darcy
 * @since JDK1.0
 */
public final class Float extends Number implements Comparable<Float> {

  /**
   * A constant holding the positive infinity of type
   * {@code float}. It is equal to the value returned by
   * {@code Float.intBitsToFloat(0x7f800000)}.
   */
  public static final float POSITIVE_INFINITY = 1.0f / 0.0f;

  /**
   * A constant holding the negative infinity of type
   * {@code float}. It is equal to the value returned by
   * {@code Float.intBitsToFloat(0xff800000)}.
   */
  public static final float NEGATIVE_INFINITY = -1.0f / 0.0f;

  /**
   * A constant holding a Not-a-Number (NaN) value of type
   * {@code float}.  It is equivalent to the value returned by
   * {@code Float.intBitsToFloat(0x7fc00000)}.
   */
  public static final float NaN = 0.0f / 0.0f;

  /**
   * A constant holding the largest positive finite value of type
   * {@code float}, (2-2<sup>-23</sup>)&middot;2<sup>127</sup>.
   * It is equal to the hexadecimal floating-point literal
   * {@code 0x1.fffffeP+127f} and also equal to
   * {@code Float.intBitsToFloat(0x7f7fffff)}.
   */
  public static final float MAX_VALUE = 0x1.fffffeP+127f; // 3.4028235e+38f

  /**
   * A constant holding the smallest positive normal value of type
   * {@code float}, 2<sup>-126</sup>.  It is equal to the
   * hexadecimal floating-point literal {@code 0x1.0p-126f} and also
   * equal to {@code Float.intBitsToFloat(0x00800000)}.
   *
   * @since 1.6
   */
  public static final float MIN_NORMAL = 0x1.0p-126f; // 1.17549435E-38f

  /**
   * A constant holding the smallest positive nonzero value of type
   * {@code float}, 2<sup>-149</sup>. It is equal to the
   * hexadecimal floating-point literal {@code 0x0.000002P-126f}
   * and also equal to {@code Float.intBitsToFloat(0x1)}.
   */
  public static final float MIN_VALUE = 0x0.000002P-126f; // 1.4e-45f

  /**
   * Maximum exponent a finite {@code float} variable may have.  It
   * is equal to the value returned by {@code
   * Math.getExponent(Float.MAX_VALUE)}.
   *
   * @since 1.6
   */
  public static final int MAX_EXPONENT = 127;

  /**
   * Minimum exponent a normalized {@code float} variable may have.
   * It is equal to the value returned by {@code
   * Math.getExponent(Float.MIN_NORMAL)}.
   *
   * @since 1.6
   */
  public static final int MIN_EXPONENT = -126;

  /**
   * The number of bits used to represent a {@code float} value.
   *
   * @since 1.5
   */
  public static final int SIZE = 32;

  /**
   * The number of bytes used to represent a {@code float} value.
   *
   * @since 1.8
   */
  public static final int BYTES = SIZE / Byte.SIZE;

  /**
   * The {@code Class} instance representing the primitive type
   * {@code float}.
   *
   * @since JDK1.1
   */
  @SuppressWarnings("unchecked")
  public static final Class<Float> TYPE = (Class<Float>) Class.getPrimitiveClass("float");

  /**
   * Returns a string representation of the {@code float}
   * argument. All characters mentioned below are ASCII characters.
   * <ul>
   * <li>If the argument is NaN, the result is the string
   * "{@code NaN}".
   * <li>Otherwise, the result is a string that represents the sign and
   * magnitude (absolute value) of the argument. If the sign is
   * negative, the first character of the result is
   * '{@code -}' ({@code '\u005Cu002D'}); if the sign is
   * positive, no sign character appears in the result. As for
   * the magnitude <i>m</i>:
   * <ul>
   * <li>If <i>m</i> is infinity, it is represented by the characters
   * {@code "Infinity"}; thus, positive infinity produces
   * the result {@code "Infinity"} and negative infinity
   * produces the result {@code "-Infinity"}.
   * <li>If <i>m</i> is zero, it is represented by the characters
   * {@code "0.0"}; thus, negative zero produces the result
   * {@code "-0.0"} and positive zero produces the result
   * {@code "0.0"}.
   * <li> If <i>m</i> is greater than or equal to 10<sup>-3</sup> but
   * less than 10<sup>7</sup>, then it is represented as the
   * integer part of <i>m</i>, in decimal form with no leading
   * zeroes, followed by '{@code .}'
   * ({@code '\u005Cu002E'}), followed by one or more
   * decimal digits representing the fractional part of
   * <i>m</i>.
   * <li> If <i>m</i> is less than 10<sup>-3</sup> or greater than or
   * equal to 10<sup>7</sup>, then it is represented in
   * so-called "computerized scientific notation." Let <i>n</i>
   * be the unique integer such that 10<sup><i>n</i> </sup>&le;
   * <i>m</i> {@literal <} 10<sup><i>n</i>+1</sup>; then let <i>a</i>
   * be the mathematically exact quotient of <i>m</i> and
   * 10<sup><i>n</i></sup> so that 1 &le; <i>a</i> {@literal <} 10.
   * The magnitude is then represented as the integer part of
   * <i>a</i>, as a single decimal digit, followed by
   * '{@code .}' ({@code '\u005Cu002E'}), followed by
   * decimal digits representing the fractional part of
   * <i>a</i>, followed by the letter '{@code E}'
   * ({@code '\u005Cu0045'}), followed by a representation
   * of <i>n</i> as a decimal integer, as produced by the
   * method {@link java.lang.Integer#toString(int)}.
   *
   * </ul>
   * </ul>
   * How many digits must be printed for the fractional part of
   * <i>m</i> or <i>a</i>? There must be at least one digit
   * to represent the fractional part, and beyond that as many, but
   * only as many, more digits as are needed to uniquely distinguish
   * the argument value from adjacent values of type
   * {@code float}. That is, suppose that <i>x</i> is the
   * exact mathematical value represented by the decimal
   * representation produced by this method for a finite nonzero
   * argument <i>f</i>. Then <i>f</i> must be the {@code float}
   * value nearest to <i>x</i>; or, if two {@code float} values are
   * equally close to <i>x</i>, then <i>f</i> must be one of
   * them and the least significant bit of the significand of
   * <i>f</i> must be {@code 0}.
   *
   * <p>To create localized string representations of a floating-point
   * value, use subclasses of {@link java.text.NumberFormat}.
   *
   * @param f the float to be converted.
   * @return a string representation of the argument.
   */
  public static String toString(float f) {
    return FloatingDecimal.toJavaFormatString(f);
  }

  /**
   * Returns a hexadecimal string representation of the
   * {@code float} argument. All characters mentioned below are
   * ASCII characters.
   *
   * <ul>
   * <li>If the argument is NaN, the result is the string
   * "{@code NaN}".
   * <li>Otherwise, the result is a string that represents the sign and
   * magnitude (absolute value) of the argument. If the sign is negative,
   * the first character of the result is '{@code -}'
   * ({@code '\u005Cu002D'}); if the sign is positive, no sign character
   * appears in the result. As for the magnitude <i>m</i>:
   *
   * <ul>
   * <li>If <i>m</i> is infinity, it is represented by the string
   * {@code "Infinity"}; thus, positive infinity produces the
   * result {@code "Infinity"} and negative infinity produces
   * the result {@code "-Infinity"}.
   *
   * <li>If <i>m</i> is zero, it is represented by the string
   * {@code "0x0.0p0"}; thus, negative zero produces the result
   * {@code "-0x0.0p0"} and positive zero produces the result
   * {@code "0x0.0p0"}.
   *
   * <li>If <i>m</i> is a {@code float} value with a
   * normalized representation, substrings are used to represent the
   * significand and exponent fields.  The significand is
   * represented by the characters {@code "0x1."}
   * followed by a lowercase hexadecimal representation of the rest
   * of the significand as a fraction.  Trailing zeros in the
   * hexadecimal representation are removed unless all the digits
   * are zero, in which case a single zero is used. Next, the
   * exponent is represented by {@code "p"} followed
   * by a decimal string of the unbiased exponent as if produced by
   * a call to {@link Integer#toString(int) Integer.toString} on the
   * exponent value.
   *
   * <li>If <i>m</i> is a {@code float} value with a subnormal
   * representation, the significand is represented by the
   * characters {@code "0x0."} followed by a
   * hexadecimal representation of the rest of the significand as a
   * fraction.  Trailing zeros in the hexadecimal representation are
   * removed. Next, the exponent is represented by
   * {@code "p-126"}.  Note that there must be at
   * least one nonzero digit in a subnormal significand.
   *
   * </ul>
   *
   * </ul>
   *
   * <table border>
   * <caption>Examples</caption>
   * <tr><th>Floating-point Value</th><th>Hexadecimal String</th>
   * <tr><td>{@code 1.0}</td> <td>{@code 0x1.0p0}</td>
   * <tr><td>{@code -1.0}</td>        <td>{@code -0x1.0p0}</td>
   * <tr><td>{@code 2.0}</td> <td>{@code 0x1.0p1}</td>
   * <tr><td>{@code 3.0}</td> <td>{@code 0x1.8p1}</td>
   * <tr><td>{@code 0.5}</td> <td>{@code 0x1.0p-1}</td>
   * <tr><td>{@code 0.25}</td>        <td>{@code 0x1.0p-2}</td>
   * <tr><td>{@code Float.MAX_VALUE}</td>
   * <td>{@code 0x1.fffffep127}</td>
   * <tr><td>{@code Minimum Normal Value}</td>
   * <td>{@code 0x1.0p-126}</td>
   * <tr><td>{@code Maximum Subnormal Value}</td>
   * <td>{@code 0x0.fffffep-126}</td>
   * <tr><td>{@code Float.MIN_VALUE}</td>
   * <td>{@code 0x0.000002p-126}</td>
   * </table>
   *
   * @param f the {@code float} to be converted.
   * @return a hex string representation of the argument.
   * @author Joseph D. Darcy
   * @since 1.5
   */
  public static String toHexString(float f) {
    if (Math.abs(f) < FloatConsts.MIN_NORMAL
        && f != 0.0f) {// float subnormal
      // Adjust exponent to create subnormal double, then
      // replace subnormal double exponent with subnormal float
      // exponent
      String s = Double.toHexString(Math.scalb((double) f,
                                                     /* -1022+126 */
          DoubleConsts.MIN_EXPONENT -
              FloatConsts.MIN_EXPONENT));
      return s.replaceFirst("p-1022$", "p-126");
    } else // double string will be the same as float string
    {
      return Double.toHexString(f);
    }
  }

  /**
   * Returns a {@code Float} object holding the
   * {@code float} value represented by the argument string
   * {@code s}.
   *
   * <p>If {@code s} is {@code null}, then a
   * {@code NullPointerException} is thrown.
   *
   * <p>Leading and trailing whitespace characters in {@code s}
   * are ignored.  Whitespace is removed as if by the {@link
   * String#trim} method; that is, both ASCII space and control
   * characters are removed. The rest of {@code s} should
   * constitute a <i>FloatValue</i> as described by the lexical
   * syntax rules:
   *
   * <blockquote>
   * <dl>
   * <dt><i>FloatValue:</i>
   * <dd><i>Sign<sub>opt</sub></i> {@code NaN}
   * <dd><i>Sign<sub>opt</sub></i> {@code Infinity}
   * <dd><i>Sign<sub>opt</sub> FloatingPointLiteral</i>
   * <dd><i>Sign<sub>opt</sub> HexFloatingPointLiteral</i>
   * <dd><i>SignedInteger</i>
   * </dl>
   *
   * <dl>
   * <dt><i>HexFloatingPointLiteral</i>:
   * <dd> <i>HexSignificand BinaryExponent FloatTypeSuffix<sub>opt</sub></i>
   * </dl>
   *
   * <dl>
   * <dt><i>HexSignificand:</i>
   * <dd><i>HexNumeral</i>
   * <dd><i>HexNumeral</i> {@code .}
   * <dd>{@code 0x} <i>HexDigits<sub>opt</sub>
   * </i>{@code .}<i> HexDigits</i>
   * <dd>{@code 0X}<i> HexDigits<sub>opt</sub>
   * </i>{@code .} <i>HexDigits</i>
   * </dl>
   *
   * <dl>
   * <dt><i>BinaryExponent:</i>
   * <dd><i>BinaryExponentIndicator SignedInteger</i>
   * </dl>
   *
   * <dl>
   * <dt><i>BinaryExponentIndicator:</i>
   * <dd>{@code p}
   * <dd>{@code P}
   * </dl>
   *
   * </blockquote>
   *
   * where <i>Sign</i>, <i>FloatingPointLiteral</i>,
   * <i>HexNumeral</i>, <i>HexDigits</i>, <i>SignedInteger</i> and
   * <i>FloatTypeSuffix</i> are as defined in the lexical structure
   * sections of
   * <cite>The Java&trade; Language Specification</cite>,
   * except that underscores are not accepted between digits.
   * If {@code s} does not have the form of
   * a <i>FloatValue</i>, then a {@code NumberFormatException}
   * is thrown. Otherwise, {@code s} is regarded as
   * representing an exact decimal value in the usual
   * "computerized scientific notation" or as an exact
   * hexadecimal value; this exact numerical value is then
   * conceptually converted to an "infinitely precise"
   * binary value that is then rounded to type {@code float}
   * by the usual round-to-nearest rule of IEEE 754 floating-point
   * arithmetic, which includes preserving the sign of a zero
   * value.
   *
   * Note that the round-to-nearest rule also implies overflow and
   * underflow behaviour; if the exact value of {@code s} is large
   * enough in magnitude (greater than or equal to ({@link
   * #MAX_VALUE} + {@link Math#ulp(float) ulp(MAX_VALUE)}/2),
   * rounding to {@code float} will result in an infinity and if the
   * exact value of {@code s} is small enough in magnitude (less
   * than or equal to {@link #MIN_VALUE}/2), rounding to float will
   * result in a zero.
   *
   * Finally, after rounding a {@code Float} object representing
   * this {@code float} value is returned.
   *
   * <p>To interpret localized string representations of a
   * floating-point value, use subclasses of {@link
   * java.text.NumberFormat}.
   *
   * <p>Note that trailing format specifiers, specifiers that
   * determine the type of a floating-point literal
   * ({@code 1.0f} is a {@code float} value;
   * {@code 1.0d} is a {@code double} value), do
   * <em>not</em> influence the results of this method.  In other
   * words, the numerical value of the input string is converted
   * directly to the target floating-point type.  In general, the
   * two-step sequence of conversions, string to {@code double}
   * followed by {@code double} to {@code float}, is
   * <em>not</em> equivalent to converting a string directly to
   * {@code float}.  For example, if first converted to an
   * intermediate {@code double} and then to
   * {@code float}, the string<br>
   * {@code "1.00000017881393421514957253748434595763683319091796875001d"}<br>
   * results in the {@code float} value
   * {@code 1.0000002f}; if the string is converted directly to
   * {@code float}, <code>1.000000<b>1</b>f</code> results.
   *
   * <p>To avoid calling this method on an invalid string and having
   * a {@code NumberFormatException} be thrown, the documentation
   * for {@link Double#valueOf Double.valueOf} lists a regular
   * expression which can be used to screen the input.
   *
   * @param s the string to be parsed.
   * @return a {@code Float} object holding the value represented by the {@code String} argument.
   * @throws NumberFormatException if the string does not contain a parsable number.
   */
  public static Float valueOf(String s) throws NumberFormatException {
    return new Float(parseFloat(s));
  }

  /**
   * Returns a {@code Float} instance representing the specified
   * {@code float} value.
   * If a new {@code Float} instance is not required, this method
   * should generally be used in preference to the constructor
   * {@link #Float(float)}, as this method is likely to yield
   * significantly better space and time performance by caching
   * frequently requested values.
   *
   * @param f a float value.
   * @return a {@code Float} instance representing {@code f}.
   * @since 1.5
   */
  public static Float valueOf(float f) {
    return new Float(f);
  }

  /**
   * Returns a new {@code float} initialized to the value
   * represented by the specified {@code String}, as performed
   * by the {@code valueOf} method of class {@code Float}.
   *
   * @param s the string to be parsed.
   * @return the {@code float} value represented by the string argument.
   * @throws NullPointerException if the string is null
   * @throws NumberFormatException if the string does not contain a parsable {@code float}.
   * @see java.lang.Float#valueOf(String)
   * @since 1.2
   */
  public static float parseFloat(String s) throws NumberFormatException {
    return FloatingDecimal.parseFloat(s);
  }

  /**
   * Returns {@code true} if the specified number is a
   * Not-a-Number (NaN) value, {@code false} otherwise.
   *
   * @param v the value to be tested.
   * @return {@code true} if the argument is NaN; {@code false} otherwise.
   */
  public static boolean isNaN(float v) {
    return (v != v);
  }

  /**
   * Returns {@code true} if the specified number is infinitely
   * large in magnitude, {@code false} otherwise.
   *
   * @param v the value to be tested.
   * @return {@code true} if the argument is positive infinity or negative infinity; {@code false}
   * otherwise.
   */
  public static boolean isInfinite(float v) {
    return (v == POSITIVE_INFINITY) || (v == NEGATIVE_INFINITY);
  }


  /**
   * Returns {@code true} if the argument is a finite floating-point
   * value; returns {@code false} otherwise (for NaN and infinity
   * arguments).
   *
   * @param f the {@code float} value to be tested
   * @return {@code true} if the argument is a finite floating-point value, {@code false} otherwise.
   * @since 1.8
   */
  public static boolean isFinite(float f) {
    return Math.abs(f) <= FloatConsts.MAX_VALUE;
  }

  /**
   * The value of the Float.
   *
   * @serial
   */
  private final float value;

  /**
   * Constructs a newly allocated {@code Float} object that
   * represents the primitive {@code float} argument.
   *
   * @param value the value to be represented by the {@code Float}.
   */
  public Float(float value) {
    this.value = value;
  }

  /**
   * Constructs a newly allocated {@code Float} object that
   * represents the argument converted to type {@code float}.
   *
   * @param value the value to be represented by the {@code Float}.
   */
  public Float(double value) {
    this.value = (float) value;
  }

  /**
   * Constructs a newly allocated {@code Float} object that
   * represents the floating-point value of type {@code float}
   * represented by the string. The string is converted to a
   * {@code float} value as if by the {@code valueOf} method.
   *
   * @param s a string to be converted to a {@code Float}.
   * @throws NumberFormatException if the string does not contain a parsable number.
   * @see java.lang.Float#valueOf(java.lang.String)
   */
  public Float(String s) throws NumberFormatException {
    value = parseFloat(s);
  }

  /**
   * Returns {@code true} if this {@code Float} value is a
   * Not-a-Number (NaN), {@code false} otherwise.
   *
   * @return {@code true} if the value represented by this object is NaN; {@code false} otherwise.
   */
  public boolean isNaN() {
    return isNaN(value);
  }

  /**
   * Returns {@code true} if this {@code Float} value is
   * infinitely large in magnitude, {@code false} otherwise.
   *
   * @return {@code true} if the value represented by this object is positive infinity or negative
   * infinity; {@code false} otherwise.
   */
  public boolean isInfinite() {
    return isInfinite(value);
  }

  /**
   * Returns a string representation of this {@code Float} object.
   * The primitive {@code float} value represented by this object
   * is converted to a {@code String} exactly as if by the method
   * {@code toString} of one argument.
   *
   * @return a {@code String} representation of this object.
   * @see java.lang.Float#toString(float)
   */
  public String toString() {
    return Float.toString(value);
  }

  /**
   * Returns the value of this {@code Float} as a {@code byte} after
   * a narrowing primitive conversion.
   *
   * @return the {@code float} value represented by this object converted to type {@code byte}
   * @jls 5.1.3 Narrowing Primitive Conversions
   */
  public byte byteValue() {
    return (byte) value;
  }

  /**
   * Returns the value of this {@code Float} as a {@code short}
   * after a narrowing primitive conversion.
   *
   * @return the {@code float} value represented by this object converted to type {@code short}
   * @jls 5.1.3 Narrowing Primitive Conversions
   * @since JDK1.1
   */
  public short shortValue() {
    return (short) value;
  }

  /**
   * Returns the value of this {@code Float} as an {@code int} after
   * a narrowing primitive conversion.
   *
   * @return the {@code float} value represented by this object converted to type {@code int}
   * @jls 5.1.3 Narrowing Primitive Conversions
   */
  public int intValue() {
    return (int) value;
  }

  /**
   * Returns value of this {@code Float} as a {@code long} after a
   * narrowing primitive conversion.
   *
   * @return the {@code float} value represented by this object converted to type {@code long}
   * @jls 5.1.3 Narrowing Primitive Conversions
   */
  public long longValue() {
    return (long) value;
  }

  /**
   * Returns the {@code float} value of this {@code Float} object.
   *
   * @return the {@code float} value represented by this object
   */
  public float floatValue() {
    return value;
  }

  /**
   * Returns the value of this {@code Float} as a {@code double}
   * after a widening primitive conversion.
   *
   * @return the {@code float} value represented by this object converted to type {@code double}
   * @jls 5.1.2 Widening Primitive Conversions
   */
  public double doubleValue() {
    return (double) value;
  }

  /**
   * Returns a hash code for this {@code Float} object. The
   * result is the integer bit representation, exactly as produced
   * by the method {@link #floatToIntBits(float)}, of the primitive
   * {@code float} value represented by this {@code Float}
   * object.
   *
   * @return a hash code value for this object.
   */
  @Override
  public int hashCode() {
    return Float.hashCode(value);
  }

  /**
   * Returns a hash code for a {@code float} value; compatible with
   * {@code Float.hashCode()}.
   *
   * @param value the value to hash
   * @return a hash code value for a {@code float} value.
   * @since 1.8
   */
  public static int hashCode(float value) {
    return floatToIntBits(value);
  }

  /**
   * Compares this object against the specified object.  The result
   * is {@code true} if and only if the argument is not
   * {@code null} and is a {@code Float} object that
   * represents a {@code float} with the same value as the
   * {@code float} represented by this object. For this
   * purpose, two {@code float} values are considered to be the
   * same if and only if the method {@link #floatToIntBits(float)}
   * returns the identical {@code int} value when applied to
   * each.
   *
   * <p>Note that in most cases, for two instances of class
   * {@code Float}, {@code f1} and {@code f2}, the value
   * of {@code f1.equals(f2)} is {@code true} if and only if
   *
   * <blockquote><pre>
   *   f1.floatValue() == f2.floatValue()
   * </pre></blockquote>
   *
   * <p>also has the value {@code true}. However, there are two exceptions:
   * <ul>
   * <li>If {@code f1} and {@code f2} both represent
   * {@code Float.NaN}, then the {@code equals} method returns
   * {@code true}, even though {@code Float.NaN==Float.NaN}
   * has the value {@code false}.
   * <li>If {@code f1} represents {@code +0.0f} while
   * {@code f2} represents {@code -0.0f}, or vice
   * versa, the {@code equal} test has the value
   * {@code false}, even though {@code 0.0f==-0.0f}
   * has the value {@code true}.
   * </ul>
   *
   * This definition allows hash tables to operate properly.
   *
   * @param obj the object to be compared
   * @return {@code true} if the objects are the same; {@code false} otherwise.
   * @see java.lang.Float#floatToIntBits(float)
   */
  public boolean equals(Object obj) {
    return (obj instanceof Float)
        && (floatToIntBits(((Float) obj).value) == floatToIntBits(value));
  }

  /**
   * Returns a representation of the specified floating-point value
   * according to the IEEE 754 floating-point "single format" bit
   * layout.
   *
   * <p>Bit 31 (the bit that is selected by the mask
   * {@code 0x80000000}) represents the sign of the floating-point
   * number.
   * Bits 30-23 (the bits that are selected by the mask
   * {@code 0x7f800000}) represent the exponent.
   * Bits 22-0 (the bits that are selected by the mask
   * {@code 0x007fffff}) represent the significand (sometimes called
   * the mantissa) of the floating-point number.
   *
   * <p>If the argument is positive infinity, the result is
   * {@code 0x7f800000}.
   *
   * <p>If the argument is negative infinity, the result is
   * {@code 0xff800000}.
   *
   * <p>If the argument is NaN, the result is {@code 0x7fc00000}.
   *
   * <p>In all cases, the result is an integer that, when given to the
   * {@link #intBitsToFloat(int)} method, will produce a floating-point
   * value the same as the argument to {@code floatToIntBits}
   * (except all NaN values are collapsed to a single
   * "canonical" NaN value).
   *
   * @param value a floating-point number.
   * @return the bits that represent the floating-point number.
   */
  public static int floatToIntBits(float value) {
    int result = floatToRawIntBits(value);
    // Check for NaN based on values of bit fields, maximum
    // exponent and nonzero significand.
    if (((result & FloatConsts.EXP_BIT_MASK) ==
        FloatConsts.EXP_BIT_MASK) &&
        (result & FloatConsts.SIGNIF_BIT_MASK) != 0) {
      result = 0x7fc00000;
    }
    return result;
  }

  /**
   * Returns a representation of the specified floating-point value
   * according to the IEEE 754 floating-point "single format" bit
   * layout, preserving Not-a-Number (NaN) values.
   *
   * <p>Bit 31 (the bit that is selected by the mask
   * {@code 0x80000000}) represents the sign of the floating-point
   * number.
   * Bits 30-23 (the bits that are selected by the mask
   * {@code 0x7f800000}) represent the exponent.
   * Bits 22-0 (the bits that are selected by the mask
   * {@code 0x007fffff}) represent the significand (sometimes called
   * the mantissa) of the floating-point number.
   *
   * <p>If the argument is positive infinity, the result is
   * {@code 0x7f800000}.
   *
   * <p>If the argument is negative infinity, the result is
   * {@code 0xff800000}.
   *
   * <p>If the argument is NaN, the result is the integer representing
   * the actual NaN value.  Unlike the {@code floatToIntBits}
   * method, {@code floatToRawIntBits} does not collapse all the
   * bit patterns encoding a NaN to a single "canonical"
   * NaN value.
   *
   * <p>In all cases, the result is an integer that, when given to the
   * {@link #intBitsToFloat(int)} method, will produce a
   * floating-point value the same as the argument to
   * {@code floatToRawIntBits}.
   *
   * @param value a floating-point number.
   * @return the bits that represent the floating-point number.
   * @since 1.3
   */
  public static native int floatToRawIntBits(float value);

  /**
   * Returns the {@code float} value corresponding to a given
   * bit representation.
   * The argument is considered to be a representation of a
   * floating-point value according to the IEEE 754 floating-point
   * "single format" bit layout.
   *
   * <p>If the argument is {@code 0x7f800000}, the result is positive
   * infinity.
   *
   * <p>If the argument is {@code 0xff800000}, the result is negative
   * infinity.
   *
   * <p>If the argument is any value in the range
   * {@code 0x7f800001} through {@code 0x7fffffff} or in
   * the range {@code 0xff800001} through
   * {@code 0xffffffff}, the result is a NaN.  No IEEE 754
   * floating-point operation provided by Java can distinguish
   * between two NaN values of the same type with different bit
   * patterns.  Distinct values of NaN are only distinguishable by
   * use of the {@code Float.floatToRawIntBits} method.
   *
   * <p>In all other cases, let <i>s</i>, <i>e</i>, and <i>m</i> be three
   * values that can be computed from the argument:
   *
   * <blockquote><pre>{@code
   * int s = ((bits >> 31) == 0) ? 1 : -1;
   * int e = ((bits >> 23) & 0xff);
   * int m = (e == 0) ?
   *                 (bits & 0x7fffff) << 1 :
   *                 (bits & 0x7fffff) | 0x800000;
   * }</pre></blockquote>
   *
   * Then the floating-point result equals the value of the mathematical
   * expression <i>s</i>&middot;<i>m</i>&middot;2<sup><i>e</i>-150</sup>.
   *
   * <p>Note that this method may not be able to return a
   * {@code float} NaN with exactly same bit pattern as the
   * {@code int} argument.  IEEE 754 distinguishes between two
   * kinds of NaNs, quiet NaNs and <i>signaling NaNs</i>.  The
   * differences between the two kinds of NaN are generally not
   * visible in Java.  Arithmetic operations on signaling NaNs turn
   * them into quiet NaNs with a different, but often similar, bit
   * pattern.  However, on some processors merely copying a
   * signaling NaN also performs that conversion.  In particular,
   * copying a signaling NaN to return it to the calling method may
   * perform this conversion.  So {@code intBitsToFloat} may
   * not be able to return a {@code float} with a signaling NaN
   * bit pattern.  Consequently, for some {@code int} values,
   * {@code floatToRawIntBits(intBitsToFloat(start))} may
   * <i>not</i> equal {@code start}.  Moreover, which
   * particular bit patterns represent signaling NaNs is platform
   * dependent; although all NaN bit patterns, quiet or signaling,
   * must be in the NaN range identified above.
   *
   * @param bits an integer.
   * @return the {@code float} floating-point value with the same bit pattern.
   */
  public static native float intBitsToFloat(int bits);

  /**
   * Compares two {@code Float} objects numerically.  There are
   * two ways in which comparisons performed by this method differ
   * from those performed by the Java language numerical comparison
   * operators ({@code <, <=, ==, >=, >}) when
   * applied to primitive {@code float} values:
   *
   * <ul><li>
   * {@code Float.NaN} is considered by this method to
   * be equal to itself and greater than all other
   * {@code float} values
   * (including {@code Float.POSITIVE_INFINITY}).
   * <li>
   * {@code 0.0f} is considered by this method to be greater
   * than {@code -0.0f}.
   * </ul>
   *
   * This ensures that the <i>natural ordering</i> of {@code Float}
   * objects imposed by this method is <i>consistent with equals</i>.
   *
   * @param anotherFloat the {@code Float} to be compared.
   * @return the value {@code 0} if {@code anotherFloat} is numerically equal to this {@code Float};
   * a value less than {@code 0} if this {@code Float} is numerically less than {@code
   * anotherFloat}; and a value greater than {@code 0} if this {@code Float} is numerically greater
   * than {@code anotherFloat}.
   * @see Comparable#compareTo(Object)
   * @since 1.2
   */
  public int compareTo(Float anotherFloat) {
    return Float.compare(value, anotherFloat.value);
  }

  /**
   * Compares the two specified {@code float} values. The sign
   * of the integer value returned is the same as that of the
   * integer that would be returned by the call:
   * <pre>
   *    new Float(f1).compareTo(new Float(f2))
   * </pre>
   *
   * @param f1 the first {@code float} to compare.
   * @param f2 the second {@code float} to compare.
   * @return the value {@code 0} if {@code f1} is numerically equal to {@code f2}; a value less than
   * {@code 0} if {@code f1} is numerically less than {@code f2}; and a value greater than {@code 0}
   * if {@code f1} is numerically greater than {@code f2}.
   * @since 1.4
   */
  public static int compare(float f1, float f2) {
    if (f1 < f2) {
      return -1;           // Neither val is NaN, thisVal is smaller
    }
    if (f1 > f2) {
      return 1;            // Neither val is NaN, thisVal is larger
    }

    // Cannot use floatToRawIntBits because of possibility of NaNs.
    int thisBits = Float.floatToIntBits(f1);
    int anotherBits = Float.floatToIntBits(f2);

    return (thisBits == anotherBits ? 0 : // Values are equal
        (thisBits < anotherBits ? -1 : // (-0.0, 0.0) or (!NaN, NaN)
            1));                          // (0.0, -0.0) or (NaN, !NaN)
  }

  /**
   * Adds two {@code float} values together as per the + operator.
   *
   * @param a the first operand
   * @param b the second operand
   * @return the sum of {@code a} and {@code b}
   * @jls 4.2.4 Floating-Point Operations
   * @see java.util.function.BinaryOperator
   * @since 1.8
   */
  public static float sum(float a, float b) {
    return a + b;
  }

  /**
   * Returns the greater of two {@code float} values
   * as if by calling {@link Math#max(float, float) Math.max}.
   *
   * @param a the first operand
   * @param b the second operand
   * @return the greater of {@code a} and {@code b}
   * @see java.util.function.BinaryOperator
   * @since 1.8
   */
  public static float max(float a, float b) {
    return Math.max(a, b);
  }

  /**
   * Returns the smaller of two {@code float} values
   * as if by calling {@link Math#min(float, float) Math.min}.
   *
   * @param a the first operand
   * @param b the second operand
   * @return the smaller of {@code a} and {@code b}
   * @see java.util.function.BinaryOperator
   * @since 1.8
   */
  public static float min(float a, float b) {
    return Math.min(a, b);
  }

  /**
   * use serialVersionUID from JDK 1.0.2 for interoperability
   */
  private static final long serialVersionUID = -2671257302660747028L;
}
